Simple demonstration how AspectJ fails in jars, see SO question: http://stackoverflow.com/questions/26802394/running-aspectj-causes-nosuchmethoderror-aspect-aspectof
If the TraceAspect.java is in the annotation module, then calling MainActivity.init() will fail with an java.lang.NoSuchMethodError: com.test.sample.annotation.TraceAspect.aspectOf exception.
If the TraceAspect.java is moved to the app module, then the advised code is executed properly.